How can I share a single page of the pdf or other documents in iOS?

The trick with "Print" on iOS

1. On opened document click Share -> Print
2. In Printer Options select Range and choose pages you need to share
3. Now you need to scroll pages carousel to the chosen pages (this part is most annoying when you have 10+ pages, and the hell for 100+)
4. Pinch out one of the chosen pages (you can't pinch unchosen pages, this is why you should scroll to the first chosen one)
5. You will see another preview screen with only chosen pages with the Share button
6. Now you can share these pages wherever you want

pros: shares one or multiple pages in original quality cons: pretty tricky for big documents

1. Open the PDF in Preview, open the left sidebar to show the miniatures.
2. Now select in the miniatures all the pages you don't need and delete them (Command - backspace). Use the Shift key to select a range of pages.
3. Select the File menu while holding the option key and select 'Save as'. Now the saved file is a PDF with just the remaining page.
4. Be sure not to overwrite the original file!

Of course, you can always open the Print dialog, select only the desired page and then select 'Save as PDF'.